This is brilliant! I usually find the typical one-toggle gain switch too crude to even bother with. I'm still catching up on the thread a bit, but am definitely on board! How do we pre-order this thing?

HOWEVER, in the headphone market, the gamut of headphones paired with headphone amplifiers is very inconsistent. This often leads to poor-matching from not enough power to drive headphones (typically: unimpressive sonics) to far too much power to drive in-ears (typically: unusable volume control + excessive hiss).

Explanation

In the headphone market, we went through virtually every current production headphone out there and what we found shocked us.

Running the rule over current production headphones, we found that there is a massive 53dB difference between the most efficient In-Ear-Monitors (IEMs) and the most inefficient headphones. This is an absolutely enormous range (think of this as the difference in loudness between a disco and a quiet library so this is NOT subtle.)

At one end of the spectrum is the HiFi Man HE-6 which is as hungry as things go. Rated at 90dB/V, this “Hummer” of a headphone needs well over 3,000mW to drive properly to good levels. Let’s categorise these as low-efficiency headphones.

BTW, for the K1000 die-hards out there, it is the "Mack juggernaut" as it is rated crazily low at 84dB/V!!!

At the other end of the spectrum are super-efficient IEMs. The Sennheiser IE800 is rated at 143dB/V and even driven by the iPhone’s paltry 15mW, you can only dial-up to 50% of its digital volume before it starts to encroach upon ear-damaging levels! Let’s categorise these as ultra-sensitive IEMs.

It is not surprising to find that we had yet to come across a headamp that can deal with this gamut let alone a DAC headamp that is portable that can deal with this full spectrum of headphones!

How does this benefit the listener?

OTW #2 is the perfect-match of headphones with the micro iDSD.

For the very first time ever, from the Sennheiser IE800 > HiFi Man HE-6, the listener is able to “dial-in” the perfect match using a combination of the micro iDSD’s Power Modes + iEMatch.

For example:

HE-6: Power mode = Turbo and iEMatch = Off

IE800: Power mode = Eco and iEMatch = Ultra-Sensitivity

These are of course, the two polar opposites so with any other headphone or in-ear-monitor, then adjust the different settings under Power mode + iEMatch to suit.

Summary Table of Power Mode + iEMatch

Technology

Description

Remarks

Approx Playing Time

HP Amp Power

• Turbo mode

8.0V/4,000mW@ 16Ohm

> 1000 mW @ 64 Ohm

6 hours

• Normal mode

4.0V/1,000mW@16Ohm

> 500 mW @ 32 Ohm

8 hours

• Eco mode

2.0V/250mW@ 16Ohm

> 250 mW @ 16 Ohm

12 hours

Technology

Description

Remarks

iEMatch

• Ultra-Sensitivity

eg Sennheiser IE800/Shure SE535

• High-Sensitivity

eg Ultimate Ears UE900/Sennheiser Momentum

• Off

eg On-Ear or Over-Ear headphones

Once this has been dialled-in to suit the listener, then the analogue volume control of the micro iDSD can be cranked up to 12 o’ clock or more where it will really start to bloom and let your music shine through.

ps. For Kugino. If England loses today, we may not have upload OTW#2 for one week. So we thought we'd better get this Outta The Way (OTW)

This matching of the micro to the actual headphones/IEMs used is a REALLY nice feature.